Atlantoaxial non-fusion posterior dynamic internal fixation system

Abstract

The application relates to a non-fusion posterior dynamic internal fixation system for atlantoaxial vertebrae, which comprises two internal fixation units arranged symmetrically and identically. The internal fixation unit comprises a atlas ball screw, two rotating pair sleeves, two locking screws, an atlas rotating connecting rod, a pivot rotating connecting rod and a pivot ball screw, the atlas ball screw has a first thread structure on the outer side of one end and is hinged to the first rotating pair sleeve, the first locking screw is connected with the first rotating pair sleeve, one end of the atlas rotating connecting rod is rotationally connected with the first rotating pair sleeve, the other end is rotationally connected with one end of the pivot rotating connecting rod, the other end of the pivot rotating connecting rod is rotationally connected with the second rotating pair sleeve, the pivot ball screw has a second thread structure on the outer side of one end and is hinged to the second rotating pair sleeve, and the second locking screw is connected with the second rotating pair sleeve. The internal fixation system can ensure the stability of the atlantoaxial vertebrae, can retain the normal activity of the atlantoaxial vertebrae, and has a simple structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a non-fusion posterior atlantoaxial dynamic internal fixation system for bone surgery. BACKGROUND

[0002] The cervical spine is extremely important for human activity, can support the skull to have very good stability, so as to make the human body have good coordination; the cervical spine with complete structure can reduce the impact on the spine and nerves and protect blood vessels; the cervical spine also has the function of movement, which can make people complete a series of head movements, and the movement of the human head to complete various postures can be regarded as the result of the coupling of the cervical spine movement. The movement of the cervical spine in the anatomical coordinate system can be divided into flexion, extension, rotation and lateral flexion, and the cervical range of motion (CROM) refers to the degree of activity of the six movements. Among them, the atlantoaxial joint composed of atlas (C1) and axis (C2) is mainly responsible for the rotation movement of the human head, and the atlantooccipital joint composed of atlas (C1) and occipital bone (C0) is mainly responsible for the flexion and extension movement. However, the atlantoaxial joint still has the ability of flexion and extension, and the movement of the atlantoaxial joint in clinic is regarded as the movement of the atlas around the odontoid process of the axis. However, common factors such as trauma and deformity can cause atlantoaxial instability, which in turn causes joint dysfunction, and can cause symptoms such as limb weakness, limited neck movement, and difficulty in urination and defecation. In severe cases, it can cause paralysis or endanger life safety.

[0003] At present, for the treatment of reduction type atlantoaxial dislocation, the treatment method commonly used in clinic is atlantoaxial posterior bone graft internal fixation surgery, that is, implanting bone blocks into the atlantoaxial joint and fixing them by cable, metal hook and other methods. The main fixation methods include Gallie technique, Broos-Jenkins technique, Sonntag method, Halifax operation, Apofix operation, Magerl operation, etc. However, the above methods can greatly reduce or even lose the cervical range of motion of the patient, thereby affecting the quality of life of the patient. The non-fusion internal fixation system which installs the internal fixation system without implanting bone blocks gradually applies in clinic because it can provide sufficient stability and fewer complications. However, this technology can only retain a certain degree of activity in the rotation or lateral flexion direction, and cannot completely restore the normal activity of the patient in six directions.

[0004] Therefore, it is of great significance to further develop the dynamic atlantoaxial posterior internal fixation system. The prior art has made some researches on the atlantoaxial posterior dynamic internal fixation system, but all have some shortcomings. For example, Chinese patent CN101601603B discloses a posterior atlantoaxial restrictive internal fixator, which is composed of a pedicle universal screw, a atlantal connecting rod, a pivot connecting rod and a universal fixed rod. The internal fixation system largely retains the rotation and lateral bending functions of the atlantoaxial joint of the patient, but the universal fixed rod limits the flexion and extension ability of the atlantoaxial joint, so it cannot restore the normal atlantoaxial joint function of the patient; Chinese patent CN106175897B discloses an atlantoaxial dislocation reduction internal fixation device, which is provided with a sliding groove on the designed guide plate, and a gear and rack structure on the internal fixation device, which can ensure a certain range of normal activity of the patient, but the structure is too complex and the movement range cannot be determined; Chinese patent CN102225022A discloses a posterior atlantoaxial dynamic fixation device, which is mainly composed of a universal connecting vertebral plate hook. After installation, the ball head part of the pedicle screw can move, so that the patient can maintain the original physiological function. However, the relative movement part of the fixation device is only on the ball head part, which cannot guarantee the large range of activity of the patient. SUMMARY

[0005] The purpose of the present application is to provide a non-fusion posterior dynamic internal fixation system for atlantoaxial joint, which can ensure the stability of the atlantoaxial joint and retain the normal activity of the atlantoaxial joint, and has a simple structure.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: a non-fusion posterior dynamic internal fixation system for atlantoaxial joint, comprising left and right internal fixation units which are the same in structure and symmetrically arranged; the internal fixation unit comprises a atlantal ball screw, a first rotating pair sleeve, a first locking screw, a atlantal rotating connecting rod, a pivot rotating connecting rod, a second rotating pair sleeve, a second locking screw and a pivot ball screw, the atlantal ball screw has a first threaded structure on one side, and is hingedly connected with the first rotating pair sleeve on the other side, the first locking screw is connected with the first rotating pair sleeve to lock the movement of the atlantal ball screw, one end of the atlantal rotating connecting rod is rotatably connected with the first rotating pair sleeve, and the other end is rotatably connected with one end of the pivot rotating connecting rod, the other end of the pivot rotating connecting rod is rotatably connected with the second rotating pair sleeve, the pivot ball screw has a second threaded structure on one side, and is hingedly connected with the second rotating pair sleeve on the other side, and the second locking screw is connected with the second rotating pair sleeve to lock the movement of the pivot ball screw.

[0007] Further, the geometric centers of the first rotating pair sleeve of the left and right internal fixation units, the rotating pair of the atlas rotating connecting rod, the rotating pair of the atlas rotating connecting rod and the pivot rotating connecting rod, and the rotating pair of the pivot rotating connecting rod and the second rotating pair sleeve are located on the same spherical surface, the axes of the rotating pair of the first rotating pair sleeve of the left and right internal fixation units, the rotating pair of the atlas rotating connecting rod, the rotating pair of the atlas rotating connecting rod and the pivot rotating connecting rod, and the rotating pair of the pivot rotating connecting rod and the second rotating pair sleeve intersect at a point, the intersection point is a fixed spherical center, and the fixed spherical center is located on the dentate process position of the pivot vertebra.

[0008] Further, among the left and right internal fixation units, the left internal fixation unit is composed of a left atlas ball screw, a left first rotating pair sleeve, a left first locking screw, a left atlas rotating connecting rod, a left pivot rotating connecting rod, a left second rotating pair sleeve, a left second locking screw, and a left pivot ball screw; wherein the left atlas ball screw is a rod-shaped structure, has a left first threaded structure on the outer side of one end, and has a left first ball head on the other end; the left first rotating pair sleeve and the left second rotating pair sleeve are both rotating bodies with a through middle part, the geometric centers are O2 and O1 respectively, the axes are l2 and l1 respectively, the left first rotating pair sleeve and the left second rotating pair sleeve each have a left first spherical groove and a left second spherical groove inside, and the spherical centers of the left first spherical groove and the left second spherical groove are located on the axes l2 and l1 respectively, the left first rotating pair sleeve and the left second rotating pair sleeve each have a left first threaded hole and a left second threaded hole inside one end, the left first threaded hole and the left second threaded hole pass through the left first spherical groove and the left second spherical groove respectively; the left atlas rotating connecting rod is a rod-shaped structure, has a left first rotating joint and a left second rotating joint at both ends respectively, the geometric centers of the left first rotating joint and the left second rotating joint are a1 and a2 respectively, the axes are l a1 、l a2 , and the axes l a1 and l a2 intersect at a point; the left pivot rotating connecting rod is a rod-shaped structure, has a left third rotating joint and a left fourth rotating joint at both ends respectively, the geometric centers of the left third rotating joint and the left fourth rotating joint are b1 and b2 respectively, the axes are l b1 、l b2 , and the axes l b1 and l b2 intersect at a point; the left first locking screw and the left second locking screw each have a left first external thread and a left second external thread respectively, and have a left first contact surface and a left second contact surface at the front end respectively; the left pivot ball screw is a rod-shaped structure, has a left second threaded structure on the outer side of one end, and has a left second ball head on the other end.

[0009] The left second spherical groove of the left second rotary pair sleeve is hingedly connected with the left second ball head of the left pivot vertebra ball screw to form spherical movement, which is used for adjusting the axis l1 direction of the left second rotary pair sleeve; the left third rotary joint of the left pivot vertebra rotary connecting rod is rotationally connected with the left second rotary pair sleeve, so that the geometric center b1 and the geometric center O1 of the second rotary pair sleeve coincide, and the axis l b1 direction of the left first rotary pair sleeve coincide, so that the relative rotation is formed between the left first rotary pair sleeve and the left atlas rotary connecting rod; the spherical movement between the left first spherical groove and the left first ball head is fixed by adjusting the axis l2 direction of the left first rotary pair sleeve to intersect the pivot vertebra odontoid process and by the cooperation between the left first threaded hole of the left first rotary pair sleeve and the left first external thread of the left first locking screw, so that the left first contact surface of the left first locking screw is pressed against the left first ball head, the spherical movement between the left first spherical groove and the left first ball head is fixed, and the left first rotary pair sleeve is fixed on the left atlas ball screw; after the left first ball head is pressed by the left first locking screw, the relative rotation formed between the left first rotary pair sleeve and the left atlas rotary connecting rod constitutes the third rotary pair;

[0010] The left fourth rotary joint of the left pivot vertebra rotary connecting rod and the left second rotary joint of the left atlas rotary connecting rod are rotationally connected in the direction of the atlas posterior arch, so that the geometric centers a2 and b2 coincide and the axes l a2 and l b2 coincide, so that the relative rotation is formed between the left pivot vertebra rotary connecting rod and the left atlas rotary connecting rod, and the second rotary pair is constituted;

[0011] The left first spherical groove of the left first rotary pair sleeve is hingedly connected with the left first ball head of the left atlas ball screw to form spherical movement, which is used for adjusting the axis l2 direction of the left first rotary pair sleeve; the left first rotary joint of the left atlas rotary connecting rod is rotationally connected with the left first rotary pair sleeve, so that the geometric center a1 and the geometric center O2 of the left first rotary pair sleeve coincide, and the axis l a1 direction of the left first rotary pair sleeve coincide, so that the relative rotation is formed between the left first rotary pair sleeve and the left atlas rotary connecting rod; the spherical movement between the left first spherical groove and the left first ball head is fixed by adjusting the axis l2 direction of the left first rotary pair sleeve to intersect the pivot vertebra odontoid process and by the cooperation between the left first threaded hole of the left first rotary pair sleeve and the left first external thread of the left first locking screw, so that the left first contact surface of the left first locking screw is pressed against the left first ball head, the spherical movement between the left first spherical groove and the left first ball head is fixed, and the left first rotary pair sleeve is fixed on the left atlas ball screw; after the left first ball head is pressed by the left first locking screw, the relative rotation formed between the left first rotary pair sleeve and the left atlas rotary connecting rod constitutes the third rotary pair;

[0012] The right inner fixation unit is composed of a right atlas ball screw, a right first rotary pair sleeve, a right first locking screw, a right atlas rotary connecting rod, a right pivot rotary connecting rod, a right second rotary pair sleeve, a right second locking screw and a right pivot ball screw; wherein the right atlas ball screw is a rod, one end of which has a right first thread structure and the other end has a right first ball head; the right first rotary pair sleeve and the right second rotary pair sleeve are both rotary bodies with a through middle part, geometric centers of which are O4 and O3 respectively, and axes of which are l4 and l3 respectively, the right first rotary pair sleeve and the right second rotary pair sleeve have a right first spherical groove and a right second spherical groove respectively, and the spherical centers of the right first spherical groove and the right second spherical groove are located on the axes l4 and l3 respectively, the right first rotary pair sleeve and the right second rotary pair sleeve have a right first threaded hole and a right second threaded hole respectively on the inner side of one end, which pass through the right first spherical groove and the right second spherical groove; the right atlas rotary connecting rod is a rod, two ends of which have a right first rotary joint and a right second rotary joint respectively, geometric centers of the right first rotary joint and the right second rotary joint are c1 and c2 respectively, axes of the right first rotary joint and the right second rotary joint are l c1 、l c2 , and the axes l c1 and l c2 intersect at a point; the right pivot rotary connecting rod is a rod, two ends of which have a right third rotary joint and a right fourth rotary joint respectively, geometric centers of the right third rotary joint and the right fourth rotary joint are d1 and d2 respectively, axes of the right third rotary joint and the right fourth rotary joint are l d1 、l d2 , and the axes l d1 and l d2 intersect at a point; the right first locking screw and the right second locking screw have a right first outer thread and a right second outer thread respectively, and have a right first contact surface and a right second contact surface respectively on the front end; the right pivot ball screw is a rod, one end of which has a right second thread structure and the other end has a right second ball head;

[0013] The right second spherical groove of the right second rotary pair sleeve and the right second ball head of the right pivot ball screw are matched and hinged to form spherical surface movement, which is used for adjusting the direction of the axis l3 of the right second rotary pair sleeve; the right third rotary joint of the right pivot rotary connecting rod is connected with the right second rotary pair sleeve to make the geometric center d1 of the right third rotary joint coincide with the geometric center O3 of the right second rotary pair sleeve, and the axis l d1The direction of the right second rotating joint sleeve coincides with the axis l3 direction of the right second rotating joint sleeve, so that relative rotation is formed between the right second rotating joint sleeve and the right pivot rotating connecting rod; the axis l3 direction of the right second rotating joint sleeve is adjusted by the right second spherical groove so that it intersects the toothed process of the pivot, and the right second threaded hole of the right second rotating joint sleeve and the right second external thread of the right second locking screw are connected to make the contact surface of the right second locking screw press the right second ball head, so that the spherical movement between the right second spherical groove and the right second ball head is fixed, so that the right second rotating joint sleeve is fixed on the right pivot ball screw. When the right second ball head is pressed by the right second locking screw, the relative rotation formed between the right second rotating joint sleeve and the right pivot rotating connecting rod constitutes the fourth rotating joint;

[0014] The fourth right rotating joint of the right axis rotating connecting rod and the second right rotating joint of the right atlas rotating connecting rod are rotatably connected in the direction of the posterior arch of the atlas, so that the geometric centers c2 and d2 coincide and the axis l c2 and l d2 The two parts overlap, thus creating a relative rotation between the right axis rotation connecting rod and the right atlantoaxial rotation connecting rod, forming the fifth rotational pair.

[0015] The right first spherical groove of the right first rotating sleeve is hinged to the right first ball head of the right atlantoaxial ball screw, forming a spherical motion used to adjust the direction of the axis l4 of the right first rotating sleeve; the right first rotating joint of the right atlantoaxial rotating connecting rod is rotatably connected to the right first rotating sleeve, so that its geometric center c1 coincides with the geometric center O4 of the right first rotating sleeve, and the axis l of the right first rotating joint is... c1 The direction of the right first rotating sleeve coincides with the axis l4 of the right first rotating sleeve, so that the right first rotating sleeve and the right atlantoaxial rotating connecting rod form a relative rotation; the right first threaded hole of the right first rotating sleeve and the right first external thread of the right first locking screw are connected, so that the right first contact surface of the right first locking screw presses the right first ball head, thereby fixing the spherical movement between the right first spherical groove and the right first ball head, so that the right first rotating sleeve is fixed on the right atlantoaxial ball screw. When the right first ball head is pressed by the right first locking screw, the relative rotation formed between the right first rotating sleeve and the right atlantoaxial rotating connecting rod constitutes the sixth rotating pair;

[0016] The geometric centers of the first, second, third, fourth, fifth, and sixth revolute joints are located on the same sphere, and the axes of the first, second, third, fourth, fifth, and sixth revolute joints intersect at a point, which is the center of a fixed sphere, and this fixed sphere is located at the odontoid process of the axis.

[0017] Further, the left and right inner fixation units are symmetrically installed; in the left inner fixation unit, the left pivot vertebra ball screw is installed and fixed on the left side of the pivot vertebra through the left second threaded structure on the pivot vertebra ball screw, and is directed to the position of the articular surface of the left side of the pivot vertebra; the left atlas ball screw is installed and fixed on the left side of the atlas through the left first threaded structure on the atlas ball screw, and is directed to the position of the left side of the atlas; in the right inner fixation unit, the right pivot vertebra ball screw is installed and fixed on the right side of the pivot vertebra through the right second threaded structure on the pivot vertebra ball screw, and is directed to the position of the articular surface of the right side of the pivot vertebra; the right atlas ball screw is installed and fixed on the right side of the atlas through the right first threaded structure on the atlas ball screw, and is directed to the position of the right side of the atlas.

[0018] Further, the geometric centers a1, a2, b1, b2, c1, c2, d1, d2 of the left atlas rotating connecting rod, the left pivot vertebra rotating connecting rod, the right atlas rotating connecting rod, and the right pivot vertebra rotating connecting rod are located on a spherical surface with a determined radius, and the axes l a1 、l a2 、l b1 、l b2 、l c1 、l c2 、l d1 、l b2 meet at the fixed spherical center.

[0019] Further, the first to sixth rotating pairs are located on the spherical surface with the fixed spherical center, and the first to third rotating pairs cannot be located on the same plane during movement, and the fourth to sixth rotating pairs cannot be located on the same plane during movement.

[0020] Further, by adjusting the lengths of the atlas rotating connecting rod and the pivot vertebra rotating connecting rod in the left and right inner fixation units, different specifications of atlantoaxial non-fusion posterior dynamic internal fixation systems can be made to adapt to different objects.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1. In the present application, the atlas ball screw and the pivot vertebra ball screw ensure atlantoaxial reduction, and by fixing the position of the fixed spherical center of the internal fixation system, the reduction can be more stable.

[0023] 2. In the present application, each rotating pair is located on the spherical surface with the fixed spherical center, and can form spherical motion around the fixed spherical center point through relative rotation, so that the patient can ensure normal atlantoaxial activity and meet the psychological expectations of the patient.

[0024] 3、The application can adjust the size of the internal fixation device according to the difference of the atlantoaxial joint movement range of different individuals by designing the different length of the atlantoaxial rotary connecting rod and the pivot rotary connecting rod.

[0025] 4、The application has simple structure and realizes the normal activity function of the atlantoaxial joint through less parts.

[0026] 5、The internal fixation system provided by the application belongs to the non-fusion technical category, does not need to implant bone blocks for fusion, can achieve reduction effect, and reduces the body damage and patient pain. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the whole structure schematic diagram of the atlantoaxial non-fusion posterior dynamic internal fixation system of the embodiment of the application.

[0028] Figure 2 It is the structure schematic diagram of the left internal fixation unit in the embodiment of the application.

[0029] Figures 3-1 to 3-8 It is the structure schematic diagram of each component part of the left internal fixation unit in the embodiment of the application.

[0030] Figure 4 It is the structure schematic diagram of the right internal fixation unit in the embodiment of the application.

[0031] Figures 5-1 to 5-8 It is the structure schematic diagram of each component part of the right internal fixation unit in the embodiment of the application.

[0032] Figure 6 It is the connection schematic diagram of the first rotary pair in the embodiment of the application.

[0033] Figure 7 It is the connection schematic diagram of the second rotary pair in the embodiment of the application.

[0034] Figure 8 It is the connection schematic diagram of the third rotary pair in the embodiment of the application.

[0035] Figure 9 It is the connection schematic diagram of the fourth rotary pair in the embodiment of the application.

[0036] Figure 10 It is the connection schematic diagram of the fifth rotary pair in the embodiment of the application.

[0037] Figure 11 It is the connection schematic diagram of the sixth rotary pair in the embodiment of the application.

[0038] Figures 12-1 to 12-6 It is the use state schematic diagram of the atlantoaxial non-fusion posterior dynamic internal fixation system of the embodiment of the application. Figure 1The axes of rotation of each rotating pair intersect at a point on the odontoid process of the axis in use; Figures 2 The use states of looking straight, forward bending, backward stretching, rotating and lateral bending are respectively shown. DETAILED DESCRIPTION

[0039] The application will be further described below in connection with the drawings and examples.

[0040] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0041] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0042] As shown in Figures 3-1 to 3-8 The present embodiment provides a atlantoaxial non-fusion posterior dynamic internal fixation system, which comprises two internal fixation units arranged symmetrically and identically. The internal fixation unit comprises an atlas ball screw, a first rotating pair sleeve, a first locking screw, an atlas rotating connecting rod, a pivot rotating connecting rod, a second rotating pair sleeve, a second locking screw and a pivot ball screw. The atlas ball screw has a first thread structure on the outer side of one end and is hinged to the first rotating pair sleeve on the other end. The first locking screw is connected to the first rotating pair sleeve to lock the movement of the atlas ball screw. The atlas rotating connecting rod is rotatably connected to the first rotating pair sleeve on one end and to the pivot rotating connecting rod on the other end. The pivot rotating connecting rod is rotatably connected to the second rotating pair sleeve on the other end. The pivot ball screw has a second thread structure on the outer side of one end and is hinged to the second rotating pair sleeve on the other end. The second locking screw is connected to the second rotating pair sleeve to lock the movement of the pivot ball screw.

[0043] The geometric centers of the first rotating pair sleeve of the left and right internal fixation units, the rotating pair of the atlantal rotating connecting rod, the rotating pair of the atlantal rotating connecting rod and the pivot rotating connecting rod, and the rotating pair of the pivot rotating connecting rod and the second rotating pair sleeve are located on the same spherical surface, the axes of the rotating pair of the first rotating pair sleeve of the left and right internal fixation units, the rotating pair of the atlantal rotating connecting rod, the rotating pair of the atlantal rotating connecting rod and the pivot rotating connecting rod, and the rotating pair of the pivot rotating connecting rod and the second rotating pair sleeve intersect at a point, the intersection point is a fixed spherical center, and the fixed spherical center is located on the dentate process position of the pivot vertebra.

[0044] As shown in Figure 4 and Figures 5-1 to 5-8 , among the left and right internal fixation units, the left internal fixation unit is composed of 8 components and 3 rotating pairs, and the 8 components are: a left atlantal spherical screw 1, a left first rotating pair sleeve 3, a left first locking screw 7, a left atlantal rotating connecting rod 4, a left pivot rotating connecting rod 5, a left second rotating pair sleeve 2, a left second locking screw 6, and a left pivot spherical screw 8. The left atlantal spherical screw 1 is a rod-shaped structure, has a left first threaded structure 1.1 on the outer side of one end, and has a left first spherical head 1.2 on the other end. The left first rotating pair sleeve 3 and the left second rotating pair sleeve 2 are both rotating bodies with a through hole in the middle, the geometric centers are O2 and O1 respectively, the axes are l2 and l1 respectively, the left first rotating pair sleeve 3 and the left second rotating pair sleeve 2 respectively have a left first spherical groove 3.1 and a left second spherical groove 2.1 inside, and the spherical centers of the left first spherical groove 3.1 and the left second spherical groove 2.1 are located on the axes l2 and l1 respectively. The left first rotating pair sleeve 3 and the left second rotating pair sleeve 2 respectively have a left first threaded hole 3.2 and a left second threaded hole 2.2 inside one end, which pass through the left first spherical groove 3.1 and the left second spherical groove 2.1. The left atlantal rotating connecting rod 4 is a rod-shaped structure, has a left first rotating joint 4.1 and a left second rotating joint 4.2 at both ends respectively, the geometric centers of the left first rotating joint 4.1 and the left second rotating joint 4.2 are a1 and a2 respectively, the axes are l a1 , l a2 , and the axes l a1 and l b2 intersect at a point. The left pivot rotating connecting rod 5 is a rod-shaped structure, has a left third rotating joint 5.1 and a left fourth rotating joint 5.2 at both ends respectively, the geometric centers of the left third rotating joint 5.1 and the left fourth rotating joint 5.2 are b1 and b2 respectively, the axes are l b1 , l b2 , and the axes l b1 and l b2The left first locking screw 7 and the left second locking screw 6 have a left first external thread 7.1 and a left second external thread 6.1 respectively, and the front end has a left first contact surface 7.2 and a left second contact surface 6.2 respectively; the left pivot ball screw 8 is a rod, and the outer side of one end has a left second thread structure 8.1, and the other end has a left second ball head 8.2. The three rotating pairs composed of the above components are respectively: the first rotating pair, the second rotating pair, and the third rotating pair.

[0045] As shown in Figure 6 and Figure 7 , the right internal fixation unit is composed of 8 components and 3 rotating pairs, and the 8 components are respectively: the right atlas ball screw 9, the right first rotating pair sleeve 11, the right first locking screw 15, the right atlas rotating connecting rod 12, the right pivot rotating connecting rod 13, the right second rotating pair sleeve 10, the right second locking screw 14, and the right pivot ball screw 16. Among them, the right atlas ball screw 9 is a rod, and the outer side of one end has a right first thread structure 9.1, and the other end has a right first ball head 9.2; the right first rotating pair sleeve 11 and the right second rotating pair sleeve 10 are both rotating bodies with a through hole in the middle, and the geometric centers are O4 and O3 respectively, and the axes are l4 and l3 respectively, and the right first rotating pair sleeve 11 and the right second rotating pair sleeve 10 have a right first spherical groove 11.1 and a right second spherical groove 10.1 respectively inside, and the spherical centers are located on the axes l4 and l3 respectively, and the right first rotating pair sleeve 11 and the right second rotating pair sleeve 10 have a right first threaded hole 11.2 and a right second threaded hole 10.2 respectively inside one end, which penetrate the right first spherical groove 11.1 and the right second spherical groove 10.1; the right atlas rotating connecting rod 12 is a rod, and the two ends have a right first rotating joint 12.1 and a right second rotating joint 12.2 respectively, and the geometric centers of the right first rotating joint 12.1 and the right second rotating joint 12.2 are c1 and c2 respectively, and the axes are l c1 , l c2 , and the axes l c1 and l c2 meet at a point; the right pivot rotating connecting rod 13 is a rod, and the two ends have a right third rotating joint 13.1 and a right fourth rotating joint 13.2 respectively, and the geometric centers of the right third rotating joint 13.1 and the right fourth rotating joint 13.2 are d1 and d2 respectively, and the axes are l d1 , l d2 , and the axes l d1 and l d2The right first locking screw 15 and the right second locking screw 14 have right first external threads 15.1 and right second external threads 14.1 respectively, and the front ends have right first contact surfaces 15.2 and right second contact surfaces 14.2 respectively; the right pivot vertebra ball screw 16 is a rod, and the outer side of one end has a right second threaded structure 16.1, and the other end has a right second ball head 16.2. The three rotating pairs composed of the above components are respectively: the fourth rotating pair, the fifth rotating pair, and the sixth rotating pair.

[0046] In use, the left and right internal fixation units are symmetrically installed; in the left internal fixation unit, the left pivot vertebra ball screw 8 is installed and fixed on the left side of the pivot vertebra arch in the direction of the joint surface through the left second threaded structure 8.1 thereon; the left atlas ball screw 1 is installed and fixed on the left side of the atlas posterior arch in the direction of the left mass through the left first threaded structure 1.1 thereon; in the right internal fixation unit, the right pivot vertebra ball screw 16 is installed and fixed on the right side of the pivot vertebra arch in the direction of the joint surface through the right second threaded structure 16.1 thereon; the right atlas ball screw 9 is installed and fixed on the right side of the atlas posterior arch in the direction of the right mass through the right first threaded structure 9.1 thereon.

[0047] The left second ball-shaped groove 2.1 of the left second rotating pair sleeve 2 cooperates with the left second ball head 8.2 of the left pivot vertebra ball screw 8 to be hinged, forming a spherical surface movement, for adjusting the direction of the axis l1 of the left second rotating pair sleeve 2; the left third rotating joint 5.1 of the left pivot vertebra rotating connecting rod 5 is rotationally connected with the left second rotating pair sleeve 2, so that the geometric center b1 and the geometric center O1 of the second rotating pair sleeve 2 coincide, and the axis l b1 of the left third rotating joint 5.1 coincides with the direction of the axis l1 of the left second rotating pair sleeve 2, so that the left second rotating pair sleeve 2 and the left pivot vertebra rotating connecting rod 5 form a relative rotation; the direction of the axis l1 of the left second rotating pair sleeve 2 is adjusted to intersect on the pivot vertebra odontoid process through the left second ball-shaped groove 2.1, and the left second contact surface 6.2 of the left second locking screw 6 is pressed against the left second ball head 8.2 through the cooperation of the left second threaded hole 2.2 of the left second rotating pair sleeve 2 and the left second external thread 6.1 of the left second locking screw 6, so that the spherical surface movement between the left second ball-shaped groove 2.1 and the left second ball head 8.2 is fixed, and the left second rotating pair sleeve 2 is fixed on the left pivot vertebra ball screw 8, and when the left second ball head 8.2 is pressed by the left second locking screw 6, the relative rotation between the left second rotating pair sleeve 2 and the left pivot vertebra rotating connecting rod 5 constitutes the first rotating pair. The connection diagram of the first rotating pair is shown in Figure 8 .

[0048] The left fourth rotating joint 5.2 of the left pivot vertebra rotating connecting rod 5 and the left second rotating joint 4.2 of the left atlas rotating connecting rod 4 are rotationally connected in the direction of the atlas posterior arch, so that the geometric centers a2 and b2 coincide, and the axis la2 and l b2 The two parts overlap, causing relative rotation between the left axis rotation connecting rod 5 and the left atlantoaxial rotation connecting rod 4, thus forming the second revolute joint. A schematic diagram of the second revolute joint connection is shown below. Figure 9 As shown.

[0049] The left first spherical groove 3.1 of the left first rotating sleeve 3 is hinged to the left first ball head 1.2 of the left atlantoaxial ball screw 1, forming a spherical motion used to adjust the direction of the axis l2 of the left first rotating sleeve 3; the left first rotating joint 4.1 of the left atlantoaxial rotating connecting rod 4 is rotatably connected to the left first rotating sleeve 3, so that its geometric center a1 coincides with the geometric center O2 of the left first rotating sleeve 3, and the axis l2 of the left first rotating joint 4.1 is... a1 The direction of the left first rotating sleeve 3 coincides with the axis l2 of the left first rotating joint sleeve 3, so that relative rotation is formed between the left first rotating joint sleeve 3 and the left atlantoaxial rotating connecting rod 4; the left first threaded hole 3.2 of the left first rotating joint sleeve 3 and the left first external thread 7.1 of the left first locking screw 7 are engaged, so that the left first contact surface 7.2 of the left first locking screw 7 presses the left first ball head 1.2, thereby fixing the spherical movement between the left first spherical groove 3.1 and the left first ball head 1.2, so that the left first rotating joint sleeve 3 is fixed on the left atlantoaxial ball screw 1. When the left first ball head 1.2 is pressed by the left first locking screw 7, the relative rotation formed between the left first rotating joint sleeve 3 and the left atlantoaxial rotating connecting rod 4 constitutes the third rotating joint. The connection diagram of the third rotating joint is shown below. Figure 10 As shown. The left internal fixing unit is now installed.

[0050] The right second spherical groove 10.1 of the right second rotating sleeve 10 is hinged to the right second ball head 16.2 of the right pivot ball screw 16, forming a spherical motion to adjust the direction of the axis l3 of the right second rotating sleeve 10; the right third rotating joint 13.1 of the right pivot rotating connecting rod 13 is rotatably connected to the right second rotating sleeve 10, so that its geometric center d1 coincides with the geometric center O3 of the right second rotating sleeve 10, and the axis l of the right third rotating joint 13.1 is... d1The axis l3 of the right second rotary pair sleeve 10 is adjusted to coincide with the direction of the axis l2 of the right axis rotary connecting rod 12, so that the relative rotation between the right second rotary pair sleeve 10 and the right axis rotary connecting rod 12 is formed, which constitutes the fourth rotary pair. The connection diagram of the fourth rotary pair is shown in FIG. 8. Figure 11

[0051] The right fourth rotary joint 13.2 of the right axis rotary connecting rod 13 and the right second rotary joint 12.2 of the right atlas rotary connecting rod 12 are rotationally connected in the direction of the posterior arch of the atlas, so that the geometric centers c2 and d2 coincide, and the axes l c2 and l d2 coincide, so that the relative rotation between the right axis rotary connecting rod 13 and the right atlas rotary connecting rod 12 is formed, which constitutes the fifth rotary pair. The connection diagram of the fifth rotary pair is shown in FIG. 9. Figures 12-1 to 12-6

[0052] The right first spherical groove 11.1 of the right first rotary pair sleeve 11 is hingedly connected with the right first spherical head 9.2 of the right atlas ball screw 9 to form a spherical movement, which is used to adjust the direction of the axis l4 of the right first rotary pair sleeve 11; the right first rotary joint 12.1 of the right atlas rotary connecting rod 12 is rotationally connected with the right first rotary pair sleeve 11, so that the geometric center c1 of the right first rotary joint 12.1 and the geometric center O4 of the right first rotary pair sleeve 11 coincide, and the direction of the axis l c1 of the right first rotary joint 12.1 and the direction of the axis l4 of the right first rotary pair sleeve 11 coincide, so that the relative rotation between the right first rotary pair sleeve 11 and the right atlas rotary connecting rod 12 is formed; through the cooperation of the right first threaded hole 11.2 of the right first rotary pair sleeve 11 and the right first external thread 15.1 of the right first locking screw 15, the right first contact surface 15.2 of the right first locking screw 15 is pressed against the right first spherical head 9.2, so that the spherical movement between the right first spherical groove 11.1 and the right first spherical head 9.2 is fixed, so that the right first rotary pair sleeve 11 is fixed on the right atlas ball screw 9, and when the right first spherical head 9.2 is pressed by the right first locking screw 15, the relative rotation between the right first rotary pair sleeve 11 and the right atlas rotary connecting rod 12 constitutes the sixth rotary pair. The connection diagram of the sixth rotary pair is shown in FIG. 10. ​ ​​The right inner fixation unit is installed as shown.

[0053] The geometric centers of the first, second, third, fourth, fifth and sixth rotary pairs are located on the same spherical surface, and the axes of the first, second, third, fourth, fifth and sixth rotary pairs intersect at a point, which is the fixed spherical center, and the fixed spherical center is located on the dentate process position of the pivot vertebra. The geometric centers a1, a2, b1, b2, c1, c2, d1 and d2 of the left atlas rotary connecting rod 4, the left pivot rotary connecting rod 5, the right atlas rotary connecting rod 12 and the right pivot rotary connecting rod 13 are located on the spherical surface with a certain radius, and the axes l a1 , l a2 , l b1 , l b2 , l c1 , l c2 , l d1 , l d2 intersect at the fixed spherical center.

[0054] After the posterior dynamic internal fixation system is installed at the atlantoaxial joint, the movement of the atlantoaxial joint forms spherical surface movement around the fixed spherical center, so that the atlantoaxial joint can restore a certain degree of activity, and the use state diagram is as shown in ​ .

[0055] In order to ensure that the atlantoaxial joint moves within a normal range, the second rotary pair and the fifth rotary pair should be limited. First, in order to ensure that the axes of the first, second and third rotary pairs are not located in the same plane during movement, and the axes of the fourth, fifth and sixth rotary pairs are not located in the same plane during movement, thereby avoiding the occurrence of movement bifurcation; second, in order to ensure that the system moves within a limited range, thereby limiting the movement range of the atlantoaxial joint in the forward flexion, backward extension, rotation and lateral bending actions. Therefore, in this embodiment, the second rotary pair and the fifth rotary pair each have a limiting structure, so that the left atlas rotary connecting rod 4 and the left pivot rotary connecting rod 5 cannot be in the same straight line, and the right atlas rotary connecting rod 12 and the right pivot rotary connecting rod 13 cannot be in the same straight line, so that the axes of the first, second and third rotary pairs are not located in the same plane during movement, and the axes of the fourth, fifth and sixth rotary pairs are not located in the same plane during movement. The limiting treatment on the second rotary pair and the fifth rotary pair can be processed in the manner of this embodiment, that is, a limiting hole is opened on the rotary joint on the outside, so that the rotary joint on the inside can only rotate within a limited range, or other ways can be used for processing.

[0056] In the embodiment, each part of the atlantoaxial non-fusion posterior dynamic internal fixation system can be made of titanium alloy material, or made of other metal which has good compatibility with human body tissue and has certain bending strength.

[0057] In the application process of the system, different specifications and sizes of atlantoaxial non-fusion posterior dynamic internal fixation systems can be made according to actual needs, such as the size of the actual atlantoaxial skeleton of the human body, by adjusting the length of the atlantal rotary connecting rod and the pivot rotary connecting rod in the left and right internal fixation units, so as to be suitable for different groups of people.

[0058] The above is only a preferred embodiment of the present application, not other forms of limitations on the present application, any skilled in the art can use the above disclosed technical content to change or modify into equivalent embodiments of equivalent changes. But any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments without departing from the technical scheme of the present application still belongs to the protection scope of the technical scheme of the present application.

Claims

1. A atlantoaxial non-fusion posterior dynamic internal fixation system, characterized in that, The inner fixation unit comprises a C ball screw, a first rotating pair sleeve, a first locking screw, a C rotating connecting rod, a pivot rotating connecting rod, a second rotating pair sleeve, a second locking screw and a pivot ball screw. The left and right internal fixation units consist of a left atlas ball screw (1), a left first rotating sleeve (3), a left first locking screw (7), a left atlas rotating connecting rod (4), a left axis rotating connecting rod (5), a left second rotating sleeve (2), a left second locking screw (6), and a left axis ball screw (8). The left atlas ball screw (1) is rod-shaped, with a left first threaded structure (1.1) on one end and a left first ball head (1.2) on the other end. The left first rotating sleeve (3) and the left second rotating sleeve (2) are both rotating bodies with a central through-hole, their geometric centers being O2 and O1 respectively, and their axes being l2 and l1 respectively. The left second rotating sleeve (2) has a left first spherical groove (3.1) and a left second spherical groove (2.1) respectively, and the centers of the spheres are located on axes l2 and l1 respectively. The left first rotating sleeve (3) and the left second rotating sleeve (2) have left first threaded holes (3.2) and left second threaded holes (2.2) respectively, which pass through the left first spherical groove (3.1) and the left second spherical groove (2.1) respectively. The left atlantoaxial rotating connecting rod (4) is rod-shaped, and has a left first rotating joint (4.1) and a left second rotating joint (4.2) at both ends respectively. The geometric centers of the left first rotating joint (4.1) and the left second rotating joint (4.2) are a1 and a2 respectively, and the axes are l1 and l2 respectively. a1 l a2 And axis l a1 and l a2 The two axes intersect at one point; the left pivot rotating connecting rod (5) is rod-shaped, with a left third rotating joint (5.1) and a left fourth rotating joint (5.2) at its two ends respectively. The geometric centers of the left third rotating joint (5.1) and the left fourth rotating joint (5.2) are b1 and b2 respectively, and their axes are l. b1 l b2 And axis l b1 and l b2 They intersect at one point; the left first locking screw (7) and the left second locking screw (6) have left first external threads (7.1) and left second external threads (6.1) respectively, and the front ends have left first contact surfaces (7.2) and left second contact surfaces (6.2) respectively; the left pivot ball screw (8) is rod-shaped, with a left second thread structure (8.1) on the outer side of one end and a left second ball head (8.2) on the other end; The left second spherical groove (2.1) of the left second rotary pair sleeve (2) cooperates with the left second spherical head (8.2) of the left pivot vertebra ball screw (8) to be hingedly connected, forming spherical surface movement, for adjusting the axis l1 direction of the left second rotary pair sleeve (2); the left third rotary joint (5.1) of the left pivot vertebra rotary connecting rod (5) is rotationally connected with the left second rotary pair sleeve (2), so that the geometric center b1 and the geometric center O1 of the second rotary pair sleeve (2) coincide, and the axis l b1 The direction of the left third rotary joint (5.1) coincides with the axis l1 direction of the left second rotary pair sleeve (2), so that relative rotation is formed between the left second rotary pair sleeve (2) and the left pivot vertebra rotary connecting rod (5); the axis l1 direction of the left second rotary pair sleeve (2) is adjusted to intersect the pivot vertebra odontoid process through the left second spherical groove (2.1), and the left second contact surface (6.2) of the left second locking screw (6) is pressed against the left second spherical head (8.2) through the cooperation of the left second threaded hole (2.2) of the left second rotary pair sleeve (2) and the left second external thread (6.1) of the left second locking screw (6), so that the spherical surface movement between the left second spherical groove (2.1) and the left second spherical head (8.2) is fixed, so that the left second rotary pair sleeve (2) is fixed on the left pivot vertebra ball screw (8); when the left second spherical head (8.2) is pressed by the left second locking screw (6), the relative rotation formed between the left second rotary pair sleeve (2) and the left pivot vertebra rotary connecting rod (5) constitutes the first rotary pair; The left fourth rotary joint (5.2) of the left axis vertebra rotary connecting rod (5) and the left second rotary joint (4.2) of the left atlas rotary connecting rod (4) are rotatably connected in the direction of the posterior arch of the atlas, so that the geometric centers a2 and b2 coincide, and the axes l a2 and l b2 coincide, so that the left axis vertebra rotary connecting rod (5) and the left atlas rotary connecting rod (4) form relative rotation, constituting the second rotary pair; The left first spherical groove (3.1) of the left first rotary pair sleeve (3) is matched with the left first spherical head (1.2) of the left atlas ball screw (1) to be hingedly connected, forming spherical movement, for adjusting the axis l2 direction of the left first rotary pair sleeve (3); the left first rotary joint (4.1) of the left atlas rotary connecting rod (4) is rotationally connected with the left first rotary pair sleeve (3), so that the geometric center a1 and the geometric center O2 of the left first rotary pair sleeve (3) coincide, the axis l a1 direction of the left first rotary pair sleeve (3) coincide, so that the left first rotary pair sleeve (3) and the left atlas rotary connecting rod (4) form relative rotation; the left first threaded hole (3.2) of the left first rotary pair sleeve (3) is matched with the left first external thread (7.1) of the left first locking screw (7) to be connected, so that the left first contact surface (7.2) of the left first locking screw (7) is pressed against the left first spherical head (1.2), thereby fixing the spherical movement between the left first spherical groove (3.1) and the left first spherical head (1.2), so that the left first rotary pair sleeve (3) is fixed on the left atlas ball screw (1); when the left first spherical head (1.2) is pressed by the left first locking screw (7), the relative rotation between the left first rotary pair sleeve (3) and the left atlas rotary connecting rod (4) constitutes the third rotary pair. The right inner fixation unit is composed of a right atlas ball screw (9), a right first rotary pair sleeve (11), a right first locking screw (15), a right atlas rotary connecting rod (12), a right pivot rotary connecting rod (13), a right second rotary pair sleeve (10), a right second locking screw (14), and a right pivot ball screw (16). The right atlas ball screw (9) is a rod, and has a right first threaded structure (9.1) on one end of the outer side and a right first ball head (9.2) on the other end. The right first rotary pair sleeve (11) and the right second rotary pair sleeve (10) are both rotary bodies with a through middle, and the geometric centers are O4 and O3, and the axes are l4 and l3. The right first rotary pair sleeve (11) and the right second rotary pair sleeve (10) have a right first spherical groove (11.1) and a right second spherical groove (10.1) respectively, and the spherical centers are located on the axes l4 and l3. The right first rotary pair sleeve (11) and the right second rotary pair sleeve (10) have a right first threaded hole (11.2) and a right second threaded hole (10.2) respectively on one end of the inner side, which pass through the right first spherical groove (11.1) and the right second spherical groove (10.1). The right atlas rotary connecting rod (12) is a rod, and has a right first rotary joint (12.1) and a right second rotary joint (12.2) on both ends. The geometric centers of the right first rotary joint (12.1) and the right second rotary joint (12.2) are c1 and c2, and the axes are l c1 、l c2 , and the axes l c1 and l c2 intersect at a point. The right pivot rotary connecting rod (13) is a rod, and has a right third rotary joint (13.1) and a right fourth rotary joint (13.2) on both ends. The geometric centers of the right third rotary joint (13.1) and the right fourth rotary joint (13.2) are d1 and d2, and the axes are l d1 、l d2 , and the axes l d1 and l d2 intersect at a point. The right first locking screw (15) and the right second locking screw (14) have a right first outer thread (15.1) and a right second outer thread (14.1) respectively, and have a right first contact surface (15.2) and a right second contact surface (14.2) on the front end. The right pivot ball screw (16) is a rod, and has a right second threaded structure (16.1) on one end of the outer side and a right second ball head (16.2) on the other end. The right second spherical groove (10.1) of the right second rotary pair sleeve (10) cooperates with the right second spherical head (16.2) of the right pivot vertebra ball screw (16) to be hingedly connected, forming spherical surface movement, for adjusting the axis l3 direction of the right second rotary pair sleeve (10); the right third rotary joint (13.1) of the right pivot vertebra rotary connecting rod (13) is rotationally connected with the right second rotary pair sleeve (10), so that the geometric center d1 and the geometric center O3 of the right second rotary pair sleeve (10) coincide, and the axis l d1 The axis l3 direction of the right second rotary pair sleeve (10) coincides with the axis l4 direction of the right third rotary joint (13.1), so that relative rotation is formed between the right second rotary pair sleeve (10) and the right pivot vertebra rotary connecting rod (13); the axis l3 direction of the right second rotary pair sleeve (10) is adjusted through the right second spherical groove (10.1) to intersect on the pivot vertebra odontoid process, and the right second contact surface (14.2) of the right second locking screw (14) is pressed against the right second spherical head (16.2) through the cooperation of the right second threaded hole (10.2) of the right second rotary pair sleeve (10) and the right second external thread (14.1) of the right second locking screw (14), so that the spherical surface movement between the right second spherical groove (10.1) and the right second spherical head (16.2) is fixed, so that the right second rotary pair sleeve (10) is fixed on the right pivot vertebra ball screw (16), and when the right second spherical head (16.2) is pressed by the right second locking screw (14), the relative rotation formed between the right second rotary pair sleeve (10) and the right pivot vertebra rotary connecting rod (13) constitutes the fourth rotary pair; The right fourth rotary joint (13.2) of the right axis vertebra rotary connecting rod (13) and the right second rotary joint (12.2) of the right atlas rotary connecting rod (12) are rotatably connected in the direction of the posterior arch of the atlas, so that the geometric centers c2 and d2 coincide, and the axes l c2 and l d2 coincide, so that the right axis vertebra rotary connecting rod (13) and the right atlas rotary connecting rod (12) form relative rotation, constituting the fifth rotary pair; The right first spherical groove (11.1) of the right first rotary pair sleeve (11) is matched with the right first spherical head (9.2) of the right atlas ball screw (9) to be hingedly connected, forming spherical movement, for adjusting the axis l4 direction of the right first rotary pair sleeve (11); the right first rotary joint (12.1) of the right atlas rotary connecting rod (12) is rotationally connected with the right first rotary pair sleeve (11), so that the geometric center c1 and the geometric center O4 of the right first rotary pair sleeve (11) coincide, the axis l c1 of the right first rotary joint (12.1) coincides with the axis l4 direction of the right first rotary pair sleeve (11), so that relative rotation is formed between the right first rotary pair sleeve (11) and the right atlas rotary connecting rod (12); the right first threaded hole (11.2) of the right first rotary pair sleeve (11) is matched with the right first external thread (15.1) of the right first locking screw (15) to be connected, so that the right first contact surface (15.2) of the right first locking screw (15) is pressed against the right first spherical head (9.2), thereby fixing the spherical movement between the right first spherical groove (11.1) and the right first spherical head (9.2), so that the right first rotary pair sleeve (11) is fixed on the right atlas ball screw (9); after the right first spherical head (9.2) is pressed by the right first locking screw (15), the relative rotation formed between the right first rotary pair sleeve (11) and the right atlas rotary connecting rod (12) constitutes the 6th rotary pair; The geometric centers of the first rotating pair, the second rotating pair, the third rotating pair, the fourth rotating pair, the fifth rotating pair and the sixth rotating pair are located on the same spherical surface, and the axes of the first rotating pair, the second rotating pair, the third rotating pair, the fourth rotating pair, the fifth rotating pair and the sixth rotating pair intersect at a point, which is the fixed spherical center, and the fixed spherical center is located on the dentate process position of the pivot vertebra.

2. The atlantoaxial non-fusion posterior dynamic fixation system according to claim 1, wherein, The left and right inner fixation units are symmetrically installed; in the left inner fixation unit, the left pivot ball screw (8) is installed and fixed on the left side of the pivot vertebra through the left second threaded structure (8.1) on the pivot ball screw, which is located in the direction of the left side of the joint surface; the left C ball screw (1) is installed and fixed on the left side of the C vertebra through the left first threaded structure (1.1) on the C ball screw, which is located in the direction of the left block; in the right inner fixation unit, the right pivot ball screw (16) is installed and fixed on the right side of the pivot vertebra through the right second threaded structure (16.1) on the pivot ball screw, which is located in the direction of the joint surface; the right C ball screw (9) is installed and fixed on the right side of the C vertebra through the right first threaded structure (9.1) on the C ball screw, which is located in the direction of the right block.

3. The atlantoaxial non-fusion posterior dynamic fixation system according to claim 1, wherein, The geometric centers a1, a2, b1, b2, c1, c2, d1, d2 of the left atlas rotary connecting rod (4), the left pivot rotary connecting rod (5), the right atlas rotary connecting rod (12), and the right pivot rotary connecting rod (13) are located on a radius-determined spherical surface, and the axis l a1 a2 b1 b2 c1 c2 d1 d2 meet at the fixed spherical center.​​​​​​​ 4. The atlantoaxial non-fusion posterior dynamic fixation system according to claim 1, wherein, The second rotating pair and the fifth rotating pair are respectively provided with limiting structures, so that the left C rotating connecting rod (4) and the left pivot rotating connecting rod (5) cannot be in the same straight line, and the right C rotating connecting rod (12) and the right pivot rotating connecting rod (13) cannot be in the same straight line, so that the axes of the first rotating pair, the second rotating pair and the third rotating pair cannot be located in the same plane during movement, and the axes of the fourth rotating pair, the fifth rotating pair and the sixth rotating pair cannot be located in the same plane during movement.

5. The atlantoaxial non-fusion posterior dynamic fixation system of claim 1, wherein, By adjusting the length of the C rotating connecting rod and the pivot rotating connecting rod in the left and right inner fixation units, a C1-C2 non-fusion posterior dynamic internal fixation system of different specifications and sizes is made to adapt to different objects.

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